Stoker



Dec.4 27, 1938. v W. fv, SAUTER I 2,141,620

' STOKER Filed May 28, 1937 3 Sheets-Sheet 3 im um l @mu um PatentedDec. 27, 1938 UNITE-D STATS Application May 28, 1937, Serial N0. 145,211

14 Claims.

This invention relates to furnace stokers, and more particularly tostokers of the multiple re- Y tort underfeed type.

One object of the present invention is to provide an improved fluidcooled system for stokers of the stated character which functions toprotect the grates thereof against molten ash and clinker formations.

Another and more specific object is to provide onel or more fluidconducting tubes in cooling relation with each of the tuyre rows andportions of the front wall of the ash pocket of the stoker, and one ormore tubes above each of the retorts, thereby forming a slag screenacross the Stoker which acts to chill the molten ash before coming incontact with the grates thereof. The tubes overlying ther retorts extendrearwardly and may terminate in the lower header of the bridge wall.These extensions lie in the hot Zone at the top of the ash pocket andthereby7 prevent the fusion of the ash into largeclinker masses.

Other and further objects will become apparent as the description of theinvention progresses.

Of the drawings:

Fig. 1 is a longitudinal sectional view taken through one of the retortsof a rStoker showing the preferred type of fluid cooling system appliedto a stoker of the Crusher pit type.

Fig. 2 is a plan view partly in section taken substantially along line2-2 of Fig. 1.

Fig. 3 is a sectional, elevational view taken substantially along line3-3 of Fig. l.

Fig. 4 is a longitudinal sectional View taken through one of the retortsof a Stoker showing the fluid cooling system applied to a stoker of thedump plate type.

Fig. 5 is a sectional elevational view taken substantially along line5-5 of Fig. 4.

Fig. 6 is a longitudinal, sectional view taken through the lower end ofa Stoker showing an alternative arrangement of tubes of the fluidcooling section, and

Fig. 7 is a sectional view taken substantially along line 'I-1 of Fig.6.

Referring first to Figs. l to 3 of the drawings, the numeral Idesignates generally a furnace equipped in the present instance with amultiple retort, underfeed stoker 2. Stoker 2 consists of a series ofalternately disposed retorts 3 and tuyre rows 4, each retort havingprovided in the bottom thereof a series of alternately disposed pushers5 and dead plates 6. Fuel from hoppers I is fed to the retorts 3 by rams8 driven by any suitable power mechanism 9. The pushers 5 are alsodriven by the power mechanism 9 through a link and lever mechanismindicated generally at I0. An extended dead or coal plate II is providedat the lower end of each retort, the rearwardly Vdisposed ends of whichbeing curved downwardly, as shown at I2, forming an 5 overfeed section.The rearwardly disposed end of stoker 2 terminates in a transverse a'shpocket I3, having a pair of Crusher rolls I4 provided at the bottomthereof. Crusher rolls I are supported in any suitable manner onstructural 10 supporting members I5.

Each tuyre row 4, as shown in Figs. 1 and 2, has mounted thereon a pairof uid conducting tubes I3. These tubes extend upwardly and form aportion of the exposed surface of the front '15 wall I1 of the furnaceI. The lower ends of these tubes are bent downwardly and forwardly, asshown at I8, and form a portion of the front vwall I9 of ash pocket I3and terminate in a transverse header 2li mounted in any suitable -20manner near the lower end of the ash pocket. The upper ends of tubes I6terminate in one of the steam drums of a boiler (not shown).

Mounted above each retort v3 and extending longitudinally thereof is atubeY 2l. The upper 425 ends of these tubes extend vertically inabutting relation with front walls I'I, and also terminate in one of thesteam drums of the boiler. The lower ends of tubes 2| extend across thetop of the ash pocket I3, and are bent downwardly, 3o as shown at 2l',thereby forming a portion of the rear or bridge wall 22 of the furnace.The tubes 2| are then bent at their lower ends, as shown at 23, andextend rearwardly and terminate in a transverse header 24, whichreceives 35 the usual tubes 25 provided in the rear wall.

Pivotally mounted in brackets 26 and 21 are a series of Crusher plates28 and 29 respectively, which cooperate with rolls I4 toy crush and feedthe ash into an ash pit 3B disposed therebe- 40 neath. Air is suppliedto the tuyre rows of the stoker from a plenum chamber 3l, which in turnreceives its air from any suitable fan or blower mechanism (not shown)through a communicating passage 32. Draft air is supplied to the lower45 end of the stoker from a second chamber 33 disposed therebeneath,which communicates with plenum chamber 3l through a communicatingpassage 34 having an adjustable damper 35 provided therein.

Headers 20 and 2&3 are connected to the boiler by downcomer connections36 and 31 respectively. As shown in Fig. 1, the tubes 2I make a smallerangle with a horizontal plane than tubes I6, so that a space 38 isprovided between these tubes 55 and the upper surface of coal plates Il.By this arrangement the fuel fed by the lowermost pushers 5 may passthrough these passages, as well as at the sides thereof, and thuspaclnng of the fuel is prevented. By the arrangement of tubes i6 and 2ijust described, it will be observed that a fluid cooled slag screen isprovided across the entire width of the stoker which functions to chillthe molten ash flowing toward the fuel supporting structure thereofbefore it comes in contact therewith. Damage to the stoker is thusprevented. It will also be observed that the tubes 2l exend over the topof the ash pocket, and thereby chill the ash contained therein toprevent the same from fusing into large clinker masses.

danger of clogging due to large clinker formations is prevented. Thelower ends of the tubes 2i also form a portion of the lower rear wall22, and lie in substantially parallel relation with the tubes 25 of theYrear wall proper. By this ar rangement the portion of the rear wall ofthe ash pocket i3, which is subjected to the greatest heat, iseffectively cooled. The portions of tubes 25 extending above tubes 2E inthe rear wall are bent slightly, as shown at fit, so that the upperextremities thereof are substantially equally spaced across the width ofthe rear wall 22.

Figs. 4 and 5 show a similar arrangement of tubes in connection with anunderfeed stoker 42 of the dump plate type. This stoker also comprises aseries of alternately disposed retorts 43 and tuyre rows 45. Each tuyrerow also has provided in cooling relation therewith tubes 65 whichextend upwardly forming a portion of the exposed surface of the frontwall 46 ofthe furnace. These tubes also extend downwardly in coolingrelation with the overfeed section 41 and terminate at their lower endsin a transversely disposed header 48. In this construction also a tube 9extends longitudinally of and in spaced relation with the bottom of eachretort 43. The lower ends of tubes 49 extend across the top of an ashpocket 55) and then are bent downwardly, as shown at 5l, and terminateat the lower ends thereof in a transverse header 52 at points betweencertain of the tubes 53 of the rear wall 54 of the furnace. Thepartially consumed fuel and refuse is fed from the stoker 42 to a seriesof dump plates 55 provided at the rear of the stoker. These dump platesare mounted on a square shaft 55. Theends of shaft 56 are round andextend through suitable bearings 5l' provided in the side walls 58 ofthe furnace. A hand lever 59 secured to one end of shaft 56 is providedto actuatel the dump plates downwardly from time to time to dischargethe ashes from pocket 56 into an ash pit 60 disposed therebeneath.

In this construction, like that shown in Figs. l to 3, the tubes 45 andt9 form a fluid cooled screen across the stoker, and function to chillany molten ash flowing toward the fuel supporting structure beforecoming in contact therewith. The rearwardly disposed ends of tubes 49overlying the top of ash pocket 56 also function to prevent the ash fromfusing into large clinkers and thereby facilitate the discharge thereofinto ash pit 6U.

Figs. 6 and 7 show a still further modification of the presentinvention. In this construction the tubes 65 overlying the retorts 66 ofthe stoker 61 are arranged in substantially the same plane as the tubes68 overlying the tuyre rows 69. The lower ends of tubes 65 also extendover the top of The ash contained in pocket I3 mayv then be fed at apredetermined rate and the Y the ash pocket 1U, and function to chillthe ash contained therein and thereby prevent the fusion of the ash intolarge clinker masses. Referring more particularly to Fig. 7, it will beobserved that each of the tubes 65 has welded or otherwise secured tothe lower side thereof, a longitudinally extending element 1I. Theseelements provide rigidity to the tubes S5, and also act as deflectorsfor `the fuel fed by the pushers 'i2 mounted in the bottoms of theretorts 66. It will also be noted that ithe tubes 65 are mounted incooling relation with the rearwardly disposed ends of dead plates 13 andthus serve the function of both chilling the molten ash flowing towardthe same, and also acting as a direct cooling l medium for these plates.

From the foregoing-description it is seen that effective fluid coolingsystems have been provided which form in effect slag screens across theentire width of the stoker. The tubes are substantially equally spacedacross the`width of the stoker in each instance, and thereby produce auniform condition over the entire grate area thereof. By thisarrangement of tubes any molten ash flowing toward the grate is chilledbefore coming in contact therewith, and as a result damage to the gratesor to the feeding mechanisms for the fuel is prevented. 'Ihe portions ofthe tubes extending over the ash pocket also chills the ash containedtherein, and thereby prevents the fusing of the same into large clinkermasses. By providing tubes over the retorts of the stoken-as shown anddescribed herein, it is seen that the fuel fed by the rams and pushersis deflected toward the adjacent tuyre rows. This tends to produce auniform fuel bed and insures greater efficiencies in operation.

While the embodiments herein shown and described are admirablyV adaptedto Yfulfill the objects primarily stated, it is to be understood that itis not intended to limit the invention to these embodiments sincev itmay be embodied in other forms, all coming within the scope of theclaims which follow.

What is claimed is:

' 1. A stoker having a fuel supporting portion, an ash pocket disposedat one end of said Stoker, and a series of fluid conductingmembersextending longitudinally through the fuel bed and overlying said fuelsupporting portion, some of said members extending across the top ofsaid ash pocket.

2. In a furnace having front and rear walls, the combination of astoker, said stoker extending rearwardly from said front wall and lyingin spaced relation with said rear wall, an ash pocket,

and a series of fluid conducting members extending longitudinallyof, andthrough the fuel bed supported by, said Stoker, some of said membersextending across said ash pocket and being so formed as to constitute aportion of said rear wall.

3. In a furnace, having front and rear wall, the combination of aninclined grate Stoker extending rearwardly from said front wall, an ashpocket disposed between said Stoker and rear wall, a series of fluidconducting members disposed longitudinally of, and through the fuel bedsupported by,'said Stoker, some of said members extending across saidash pocket and being formed to lie in abutting relation with said rearwall, and means for circulating a cooling medium through said members.

4. In a furnace having front and rear walls, vthe combination ofan'inclined grate stoker extending rearwardly from said front wall,`saidstoker comprisingv alternately disposed retorts and'tuyre rows, an ashpocket disposed between said stoker and rear wall, a series of fluidconducting tubes extending longitudinally of said stoker and overlyingsaid retorts and tuyre rows, some of said tubes extending rearwardlyacross the top of said ash pocket.' Y

5. In a furnace having front and rear walls, the combination of aninclined grate stoker extending rearwardly from said front wall, saidstoker comprising alternately disposed retorts and tuyre rows, an ashpocket disposed between said stoker and rear wall, a series of fluidconducting tubes extending longitudinally of said stoker and lyingadjacent said retorts and tuyre rows, the tubes lying adjacent saidretorts extending rearwardly being formed to lie in abutting relationwith said rear wall, and means for circulating a cooling medium throughsaid tubes.

6. In a furnace having front and rear walls, the combination of aninclined grate stoker, extending rearwardly from said front wall, saidstoker comprising alternately disposed retorts and tuyre rows, a seriesof dump plates provided at the rear of said Stoker, yand a series offluid conducting tubes extending longitudinally of said stoker andoverlying said retorts and tuyre rows, some of said tubes extendingrearwardly and overlying said dump plates.

'7. In a furnace, having front and rear walls, the combination of aninclined grate Stoker extending downwardly and rearwardly from saidfront wall, said Stoker comprising alternately disposed retorts andtuyre rows, one or more tubes mounted in cooling relation with each ofsaid tuyre rows, an ash pocket disposed between said stoker and rearwall, said tubes being bent downwardly so as to form a portion of thefront wall of said ash pocket, a header connected to the lower ends ofsaid tubes, a fluid conducting tube exten-ding longitudinally of each ofsaid retorts and across the top of said ash pocket, said last mentionedtubes being bent downwardly so as to form a portion of said rear wall,and a header connected to each of said last mentioned tubes.

8. In a furnace having front and rear walls, the combination of aninclined grate stoker, extending downwardly and rearwardly from saidfront wall, said stoker comprising alternately disposed retorts andtuyre rows, an ash pocket disposed between said stoker and rear Wall, aseries of spaced fluid conducting tubes mounted in cooling relation withsaid rear wall, a header connecting one end of each of said tubes, oneor more fluid conducting tubes mounted in cooling relation with each ofsaid tuyre rows, said tubes extending downwardly and forming a portionof the front wall of said ash pocket, a tube extending longitudinally ofeach of said retorts, said last mentioned tubes extending rearwardlyacross the top of said ash pocket and terminating in said header rstnamed at points located between certain of said first mentioned tubes,and means for circulating a cooling medium through all of said tubes.

9. In a furnace having front and rear walls, the combination of aninclined grate stoker, extending downwardly and rearwardly from saidfront wall, said stoker comprising alternately disposed retorts andtuyre rows, an ash pocket disposed between said stoker and rear wall, aseries of spaced fluid conducting tubes mounted in cooling relation withsaid rear wall, a header conacross the top of said ash pocket and'necting' one end yof each of said tubes, one or more-fluid conductingtubes mounted in cooling relation with each of said tuyre rows, saidtubes exten-ding downwardly and forming a portion of the front wall oflsaid ash pocket, a tube extending longitudinally of each of saidYretorts, saidlast mentioned tubes extending rearwardly across the top ofsaid ash pocket, and being bent downwardly so asto lie in abuttingrelation with said rear wall and between certain of said rst mentionedtubes, said last mentioned tubes terminating-in said header nrst named,and means for circulating a cooling medium through all of said tubes.

10. In a furnace having front and rear walls, the combination of aninclined grate stoker extending downwardly and rearwardly from saidfront wall, said stoker comprising alternately disposed retorts andtuyre rows, a series of fuel feeding elements mounted in the bottom ofeach of said retorts, a dead plate provided at the lower end of each ofsaid retorts and extending rearwardly from said fuel feeding elements,an ash pocket disposed between said stoker and rear wall, a fluidconducting tube mounted longitudinallyof each of said retorts andsubstantially midway between adjacent tuyre rows, said tubes beingdisposed in spaced relation with respect to said fuel feeding elementsand dead plates, and means for circulating a fluid cooling mediumthrough said tubes.

11. In a furnace having front and rear walls, theV combination of aninclined grate stoker extending rearwardly from said front wall, saidstoker comprising alternately disposed retorts and tuyre rows, fuelfeeding elements provided in the bottoms of said retorts, a dead plate-provided at the lower end of each retort and extending rearwardly ofsaid fuel feeding elements, an ash pocket disposed between said stokerand rear wall, one orrmore fluid conducting tubes mounted in coolingrelation with each of said tuyre rows, the lower portions of said tubesbeing bent downwardly so as to form a portion of the front wall of saidash pocket, a fluid conducting tube extending longitudinally of each ofsaid retorts and lying in spaced relation with said fuel feedingelements and dead plates, said last mentioned tubes extending rearwardlyacross pocket and being bent downwardly so as to form a portion of saidrear wall, and means for circulating cooling medium through said tubes.

12. In a furnace having front and rear walls, the combination of aninclined grate Stoker extending rearwardlyA from said front wall, saidstoker comprising alternately disposed retorts and tuyre rows, fuelfeeding elements provided in the bottom of each of said retorts, a deadplate provided at the lower end of each of said retorts and extendingrearwardly of said fuel feeding elements, said dead plates being roundedat the rearwardly disposed Aends thereof forming an overfeed section, afluid conducting tube extending longitudinally of each of said retortsand substantially midway between adjacent tuyre rows, said tubes beingdisposed in spaced relation with said fuel feeding elements, and thelower portions thereof lying in cooling relation with said dead plates,said tubes extending rearwardly across said ash pocket, and means forcirculating a" cooling medium through said tubes.

18. In a furnace having front and rear walls, the combination of astoker, said stoker extending rearwardly from said front wall andcomprising alternately disposed retorts and tuyre rows, fuel feedingelements provided in the bottom of each the top of said ash of saidretorts, a, fluid conducting tube extending longitudinally of each ofsaid retorts, and means provided at the lower side of each of said tubesfor delecting the fuel fed by said fuel feeding y elements toward saidtuyre rows.

14. In a furnace having front and rearwalls, the combination of astoker, said stoker extending rearwardly from said front wall andcomprising alternately disposed retorts Yand tuyre rows, fuel feedingelements provided in the bottom of each of said retorts, a dead platemounted in each retort at the bottom thereof and extending rearflectingthe fuel fed by said elements toward 10 their tuyreV rows.

' lWILLIAM V. SAUTER.

